Timing switch



y 1957 E. B. FARMER 2,800,536

TIMING SWITCH Filed Jan. 8, 1954 2 sheets-Shea: 1

AM I

51 5,? v 74 51 7? 63 d3 1/1? 1% 76' 11/ 155/ 55 a? 55) E. B. FARMERTIMING SWITCH July 23, 1957 2 Sheets-Sheet 2 Filed Jan. 8, 1954 PatentedJuly 23, 1957 TIBHNG SWITCH Edward B. Farmer, Waban, Mass.

Application January 8, 1954, Sfifil N0. 402,890

8 Claims. (Cl. 260-31 The invention relates to electric switch gear,especially to high speed rotary timing switches.

Objects of the invention are to provide a rotar switch which can bedriven at high speed, with a minimum of wear on the moving parts, toopen and close a circuit at predetermined times during each revolutionof a driving shaft, to provide a switch which can be continuouslyadjusted to vary and securely to hold the timing with reference to tireangular position 1' the shaft, which has means for varying therotational torque required to adjust the switch, and which can be easilyadapted to perform varied timing operations, and to provide a switchwhich is compactly and securely mounted in a housing permittingconvenient access for inspection and repair, and which has easilyobservable means for indicating the angular position of the switchingpoint with reference to the shaft at any given time.

To -accomplish these and other objects, high speed rotary timingswitches according to the invention are driven by a shaft journhlled ina base on which a switch support is rotatably mounted. Switch meanshaving relatively movable contacts and means adjacent the shaft formaking and breaking contact are mounted on the support and cam means areinterchangeably attached to the shaft for actuating the making andbreaking means at a given position thereof relatively to the base. Foradjusting the spatial relation between the switch support and the base,self-arresting means such as low pitch worm gear are provided,preferably together with a slip ring arrangement for connecting thecontacts to terminals on the base. and together with index means forindicatin the relative position of the base and the switch support,whereby the switch is operated by the cam in a predetermined position ofthe switch support relatively to the base which position,

and hence a selected phase relation between shaft rotation and thecontact making and breaking, can be established and maintained by theadjusting means, with the aid of the index means.

These and other objects and aspects of novelty of the invention willappear from the herein presented outline of its principles and practicalpossibilities together with a description of a practical embodimentillustrating its novel characteristics. These refer to drawings inwhich:

Fig. 1 is a top view of the switch;

Fig. 2 is a vertical section taken on line 2 2 of Fig. I;

Fig. 3 is a front view of the switch with the cover removed;

Fig. 4 is a horizontal section taken on line l 4 of Fig. 2; and

Fig. 5 is an exploded detail view of the cam assembly.

The switch according to the invention is mounted on a supporting basesuch as a substantially rectangular open face shell having a back wall11 (Figs. 1 and 2), and forwardly projecting top, side and bottom. walls11, 1d and 16, respectively. The open front is partially closed by afront wall strip 18 (Fig. 2) fastened across the lower part of thehousing and forming with the forward edges of the top and side walls 12,14.1, 14.2, respectively, a substantially circular opening. To this endthe portion 12.1 of the top wall (Figs. 1, 3) is made circular near itsforward edge and merges with the side walls at about the horizontaldiameter of the circular opening while the bottom wall strip 18 has acircular upper edge 18.1 (Fig. 2) which forms the lower half of thecircular opening. Towards the rear wall 11, side walls 14 and top wall12 form two substantially rectangular shoulders 22, 23 (Figs. 1, 3). Theframe has at its bottom a rearwardly extending mounting or base flange26, with a pair of slots 28 for bolts. Rear wall 11 has a rearwardlyextending bearing boss 30.

A hollow cylindrical arbor 32 (Fig. 2) having a shoulder 34 intermediateits ends is press-fitted into the bearing boss 30, with the shoulder 34abutting the inner end of the boss so that the larger portion of thearbor extends forwardly from the rear wall 11. A shaft 36 is journaledwithin the hollow arbor in spaced ball bearings 38, the inside diameterof the arbor being enlarged to form a shoulder 41. The bearings are heldin spaced relation within the enlarged portion by a spacer sleeve 42, afol lower ring 44 and a cap plate 45 fastened to the outer end of thebearing boss 30. The shaft 36 is fastened to its bearing race rings by ashoulder 47 at its forward end which engages the forward side of theforward race ring, and by a lock ring 49 set in an annular groove andengaging the rear side of the rear race ring. Forward of the shoulder 47the shaft has an end or socket portion 50 on which is mounted a cam 54(Fig. 2) in the manner shown in Fig. 5 as follows. The end portion 50has an axial socket 46 (see also Fig. 2) for the rear end of aninsulator pin 48 made for example of Bakelite. This pin is retained inthe socket 46 by means of a set screw in a tapped hole 51 of the socketwall of the shaft end portion. An insulating spacer 52, made for exampleof nylon, engages with two slots 52.1, 52.2, two corresponding studs50.1, 50.2 of the socket portion 50. The spacer 52 has on the other sidetwo further slots 52 .3, 52.4. The forward end of insulating pin 48 hasan axially tapped hole 48.1. The cam body 54, made of steel, has asleeve portion 56 with two studs 56.3, 56.4 corresponding to slots 52.3,52.4 of the spacer ring 52. The earn proper 57 is a hardened andpolished eccentric (Fig. l) terminating in a conical lubricating portion57.1. The cam body has a socket portion 57.5 for the insulating pin 48and a counterbored hole for a screw 58 (Figs. 2 and 3) fitting thetapped hole 48.1 of the pin 48. This construction provides an angularlyexact fit between cam and shaft and at the same time permits readyexchange of cam bodies simply by removing screw 58. Furthermore, spacer52 and pin 48 provide reliable electrical insulation between shaft andcam. The cam lubrication will be described below.

A hub 60 (Fig. 2) is mounted on the outside of the arbor 32 for rotationthereon with its rear end abutting a thrust ring 62, made for example ofnylon, resting against the inner end of the bearing boss 30. The hub isretained by a lock ring 64; placed between the hub end and a radialflange 66 on the forward end of the arbor 32. The hub 60 carries at itsforward end a switch support such as an open drum 68, having a forwardlyextcndiiig cylindrical wall 70 (Figs. 2 and 3), which is concentric withthe shaft 36 and for the most part projects beyond the forward edges ofthe walls of the housing. Within the drum 68 is a switch plate 72 (Figs.2 and 3) which has a circular opening 74 at its center through whichprojects the forward part of the shaft 36. The switch plate 72 issupported on the drum by means of four forwardly hi6 jecting cars 76(Figs. 2 and 3 with threaded openings for screws 78 inserted throughcorrespondingly located holes in the cylindrical wall to. The switchplate 72 is completely insulated front the drum by insulating washers81, 82, placed between the ears, the drum wall, and the heads of thescrews, and by sleeves 83 surrounding the shank of the screws where theypass through the wall.

The switch plate 72 carries the switch proper which consists of thecontacts 84 and 86 (Fig. 3) of a make and break switch. preferably ofthe conventional automotive breaker point design. The contact element 84is fast to an ear 84.1 at one end of U-shaped contact plate 88 in whichare elongate openings 90.1, 90.2 through which are inserted screws 92.1,92.2, one of which is an cccentric, for adjustnbly fastening it to theplate 72 in conventional manner. The other end of the plate 88 has fixedto its forward side a pin 94 with an insulating sleeve 96, and on thissleeve is pivoted an arm 98 which carries at its free end the othercontact 86. The arm 98 is normally urged to closed switch position. withcontact 56 in engagement with contact 84, by a bowed spring 99 fastcnedat one end to the drum wall '70 by one of the bolts 78, and at its otherend to arm 98. The arm 98 has fast to the inner side of its free end alifter 104 of an an extended high portion, or a number of high points orpeaks so that the contacts can be separated from and restored toengagement several times during each rotation of the shaft. Furthermore,cams with depressions instead of peaks can be used in order to provide anormally open instead of normally closed switch. The duration ofseparation or contact at any given time can be adjusted by means ofslots 90.1, 90.2, of plate 88 and screws 92.1, 92.2 fastening it toswitch plate 72.

The hub 60 carries a sleeve 106 (Fig. 2) of insulating material, havinga collar 108. A pair of slip rings 111 and 112 are mounted on sleeve 106between collar 108 and insulating washers 114, 116. Graphite brushes 118and 119 (Fig. 4) of conventional design are mounted, by means of brushholders 118.1 and 119.1, in the walls 14.1, 14.2 for engagementrespectively with the slip rings 112 and 111. Lead wires 122 and 124 tiethe brush holders 118.1 and 119.1 to connections 122.1 and 124.1 on aterminal strip 126 (Figs. 2 and 3) fastened to the back of the housingnear its bottom. The slip rings 111 and 112 are in turn connected to thecontacts 84 and 86 by way of lead wires 128 and 129 (Fig. 3) the formerbeing connected to the arm 98 through spring 99 and the latter to theplate 72 through one of the cars 76.

To effect rotation of the drum 68 and hence to displace the switchcontacts angularly with respect to the housing 10, thereby to advance orretard the actuation of the switch relatively to the rotation of theshaft 36, the following mechanism is provided. A worm wheel 132 (Figs. 2and 4) is made fast to the hub 60, a spacer ring 134 being interposedbetween it and the slip ring assembly. A worm 136 is mounted in theupper part of the housing in engagement with the worm wheel 132, on ahorizontally arranged worm shaft 138 which is journaled in eccentricbushings 141.1, 141.2 (Fig. 4) rotatably mounted in bearing openings142.1, 142.2 formed in the shoulders 22, 23. Set screws 144 (Fig. 3) areprovided for fixing the eccentric sleeves in any desired angularposition thus to permit movement of the axis of the shaft 138 to andfrom the center of rotation of the worm wheel. Adjusting movement towardthe worm wheel increases the torque necessary to turn the shaft, whilemovement away from the worm wheel decreases the torque. Slots 141.3,141.4 (Fig. 4) in the exposed ends of the eccentric bushings permitengagement with a spanner to turn the bushings. A hand wheel 146 (Fig.3) is fas- 4 tened to an end of the shaft 138 for rotating it. The wormand worm wheel have a low pitch so that this gear is self-locking andthe switch drum 68 securely held in any position to which it is turned.

The open end of the drum 68 is covered by a cap 148 (Figs. 1, 2, 4)having a rearwardly extending cylindrical wall 150 which meets and isconcentric with the forwardly extending walls of the shell or housing10. This cap is provided with spaced holes 152 for screws which arethreaded into bosses 154 (Fig. 4) formed on the walls of the drum, thusfastening the cap to the drum so that it will rotate therewith. Toprovide for lubrication, the cap has at its inside a concentric recess154 (Figs. 2, 4) in which is set a felt washer 156 saturated with lightoil; the forward end of the cam sleeve 57 has a conical projection 57.1which enters the washer and picks up oil therefrom feeding it to the camthus providing a film of oil for the cam surface to increase the life ofthe Bakelite lifter 104.

In order easily to indicate the angular position of the switch withrespect to the housing at any given time, a reference mark 158 (Fig. 1)is provided on the upper, curved portion of the top wall 12, and a scale159 is marked on the periphery of cap 148. The scale 159 is graduated indegrees from 0 to 360. Thus the continuous adjustment of the point ofswitch operation, through 360 of rotation can be easily controlled. Asmentioned above, if once set, it is automatically locked in position bythe worm drive.

A cable clamp 162 is fastened to a side wall of the housing toaccommodate the leads from the controlled circuit.

In operation, the shaft 36 is coupled to a driving member of thecontrolling apparatus; a typical example for the use of switch gearaccording to invention is the control of high speed punch presses whichare started and stopped by means of pneumatic clutches and of brakes,actuated by means of solenoid valves. The operation of such machinesinvolves speeds of 200 to 900 R. P. M. and ordinary switches do notstand up to continuous actu' ation at such speeds. Eqpuipment accordingto the present invention not only operates reliably at these speeds, butprovides operation of the dependent component (for example a valvesolenoid in a holding circuit) at the proper point of a cycle so thatfor example a brake actuated by the valve can be operated at the top ofthe stroke of a press, each time a stop is made.

The shaft 36 having been connected in this manner, the switch operationis adjusted by turning hand wheel 146 to establish the proper phaserelation between the switch actuation and the working cycle of thecontrolling and controlled mechanisms and circuits. It will now beevident that the adjustability through 360 permits the setting of anysuch phase relation between the switch actuation and the position of theshaft, and the secure locking of this relation thereafter. As mentionedabove, the length of the time interval during which the contacts 84, 86are opened or closed can be adjusted by shifting the contact plate 88 onthe switch plate 72 after loosening screws 92. The switch can be easilyinspected by removing cap 148 after taking out the two screws throughholes 152 which fasten the cap to bosses 154 of the drum 68; ifdefective, the switch can be easily removed. The cam 54 is likewisereadily accessible by removing cap 148 and it can be exchanged byloosening screw 58 as above described.

It will now be evident that the cam lifts contact arm 98 by means oflifter 104 when the latter encounters the raised portion or portions ofthe cam. The two contacts are connected through their respectivebrushes, slip rings and lead wires to the terminal connectors on strip126 where they are tied into the control circuit in question. Changes inphase relation such as for example due to change in press speed arecompensated for by advancing or retarding the switch element by means ofthe hand wheel 146.

It will be noted that this device can be used in circuits which can notbe grounded, because the switch assembly is insulated from the metalhousing by insulating washers and tubes 81, 82, 83. The insulatingbushing 52 provides an insulation from shaft 36, as protection againstwear of the lifted 104. If this lifter is neglected until it wears outto a degree that it lets arm 98 touch cam 54, the switch housing isstill safe and free from electrical shock potential, due to insulator52.

As mentioned above, the cam 54 can be easily exchanged by means of thecoupling arrangement shown in Fig. 5, merely by removing cap 148 andloosening screw 58 whereupon the cam can be pulled from the insulatingpin 48. The new cam can be inserted and fastened, and the cap replacedwithout affecting the relation between index, scale, cam and switchpoints.

It should be understood that the present disclosure is for the purposeof illustration only and that this invention includes all modificationsand equivalents which fall within the scope of the appended claims.

I claim:

1. A rotary timing switch comprising a supporting base; shaft meansjournalled in said base; a switch support rotatably mounted on saidbase; switch means carried by said support, having relatively movablecontacts and means for making and breaking contact thereof; cam means;means for interchangeably mounting said cam means on said shaft meansfor actuating said making and breaking means; a continuous drive,including a selfarresting transmission member, for adjusting the spatialrelation beween said base and said support; yielding conductor meansleading from said base to said support and said contracts; and indexmeans for indicating the relative position of said base and saidsupport; whereby the switch means can be variably operated byinterchangeable cam means in predetermined positions of the switchsupport relatively to the base, which positions, and hence a selectedphase relation between shaft rotation and the making and breaking ofcontact, can be established and maintained by the adjusting means.

2. A rotary timing switch comprising a supporting base; shaft meansjournalled in said base; a switch support rotatably mounted on the basecoaxially with said shaft means; switch means carried by said support,having relatively movable contacts and means for making and breakingcontact thereof; cam means; coupling means including an insulating studand slot connection for interchangeably mounting said cam means at anessentially fixed angular relation on said shaft means for actuatingsaid making and breaking means; and an automatically locking movementfor adjusting the spatial relation between said base and said support;whereby operation of the switch means can be selected by interchangingthe cam means, and whereby the position of the switch support relativelyto the base, and hence a selected phase relation between shaft rotationand the making and breaking of contact, can be established andmaintained by said coupling means and said adjusting means.

3. A rotary timing switch comprising a supporting base; shaft meansjournalled in said base; a switch support rotatably mounted on the basecoaxially with said shaft means; switch means carried by said support,having relatively movable contacts and means for making and breakingcontact thereof; cam means; coupling means for interchangeably mountingsaid cam means at an essentially fixed angular relation on the end ofsaid shaft means for actuating said making and breaking means, saidcoupling means including an insulating pin fastened in a socket at saidshaft end, stud means extending rearwardly from said cam means, and onsaid pin an insulating ring interposed between the socket and the cammeans and having slot means on either side for engaging said stud meansof socket and cam means; and an automatically locking movement foradjusting the spatial relation between said base and said support;whereby operation of the switch means can be selected by interchangingthe cam means, and whereby the position of the switch support relativelyto the base, and hence a selected phase relation between shaft rotationand the making and breaking of contact, can be established andmaintained by said coupling means and said adjusting means.

4. A rotary timing switch comprising a supporting base; shaft meansjournalled in said base; a switch support rotatably mounted on saidbase; switch means carried by said support, having contacts and meansfor making and breaking contact thereof; cam means; coupling means formounting said cam means on said shaft means for actuating said makingand breaking means; a self-arresting movement for adjusting the spatialrelation between said base and said switch support; and index means forindicating the relative position of said base and said switch support,which index means include a cover mounted on said support, said coverextending to said base to form an enclosure, and carrying a scaleplaying on an index on the base; whereby the switch means can beoperated by the cam means in predetermined positions of the switchsupport relatively to the base, which positions, and hence a selectedphase relation between shaft rotation and the making and breaking ofcontact, can be observed and set with the aid of the scale means.

5. A rotary timing switch comprising a supporting base; shaft meansjournalled in said base; a switch support rotatably mounted on saidbase; switch means carried by said support, having contacts and meansfor making and breaking contact thereof; cam means having a cam portionand a conical end portion; coupling means for mounting said cam means onsaid shaft means with said conical portion pointing away from saidsupport and with said cam position arranged for actuating said makingand breaking means; a self-arresting movement for adjusting the spatialrelation between said base and said switch support; a cover mounted onsaid support; and an oiling ring fastened inside said cover in contactwith said conical end portion; whereby the switch means can be operatedby the cam means in predetermined positions of the switch supportrelatively to the base, and said cam means is continuously lubricated bysaid oiling ring.

6. A rotary timing switch comprising a supporting base; shaft meanslournalled in said base; a switch support rotatably mounted on saidbase; switch means carried by said support, having relatively movablecontacts and means for making and breaking contact thereof; cam means;coupling means for mounting said cam means on said shaft means foractuating said making and breaking contacts; a continuous drive,including a self-arresting transmission member, for adjusting thespatial relation between said base and said switch support; yieldingcondoctor means leading from said base to said contacts, including slipring means on said switch support and corresponding brush means fastenedto said base; whereby the switch means can be operated by the cam meansin pore determined positions of the switch support relatively to thebase, which positions, and hence a selected phase relation between shaftrotation and the making and breaking of contact, can be established andessentially maintained by the adjusting means and the conductor means.

7. A rotary timing switch comprising a supporting base; shaft meansjournalled in said base; a switch support rotatably mounted on said basecoaxially with said shaft means; switch means carried by said supportbut insulated therefrom, having relatively movable contacts and meansfor making and breaking contact thereof; cam means; coupling meansincluding an insulating stud and slot connection for interchangeablymounting said cam means on said shaft means at an essentially fixedangular relation for actuating said making and breaking means;self-arresting low pitch worm gear means for adjusting the spatialrelation between said base and said support; yielding conductor meansleading from said base to said support and said contacts, including slipring means on said shaft and brush means on said base; and index meansfor indicating the relative position of said base and said support,including a cover mounted on said support and extending to said base toform an enclosure, and carrying a scale that plays on an index on saidbase; whereby the switch means can be operated by interchangeable cammeans in predetermined positions of the support relatively to the base,which positions, and hence a selected phase relation between shaftrotation and the making and breaking of contact, can be established andmaintained by means of the adjusting, conductor, and index means.

8. A rotary timing switch comprising a supporting base; shaft meansjournalled in said base; a switch support mounted on the base; switchmeans carried by said support, having relatively movable contacts andmeans for making and breaking contact thereof; earn means; couplingmeans for interchangeably mounting said cam means at an essentiallyfixed angular relation on the end of said shaft means for actuating saidmaking and breaking means, said coupling means including an insulatingpin fastened in a socket at said shaft end, stud means extendingforwardly from said socket, stud means extending rearwardly from saidcam means, and on said pin an insulating ring interposed between thesocket and the cam means and having slot means on either side forengaging said stud means of socket and cam means; whereby operation ofthe switch means can be selected by interchanging the cam means.

References Cited in the file of this patent UNITED STATES PATENTS l,28l.204 Pitts Oct. 8, 1918 2,033,477 Lang et al Mar. 10, 1936 2,074,322Bechrnan Mar. 23, 1937 2,107,470 Crawford et al Feb. 8, 1938 2,611,837Zirin Sept. 23, 1952 2,677,023 Lee Apr. 27, 1954 FOREIGN PATENTS 106,029Great Britain May 10, 1917

